+++ /dev/null
-/*******************************************************************************
- * Copyright (c) 2000, 2004 IBM Corporation and others.
- * All rights reserved. This program and the accompanying materials
- * are made available under the terms of the Common Public License v1.0
- * which accompanies this distribution, and is available at
- * http://www.eclipse.org/legal/cpl-v10.html
- *
- * Contributors:
- * IBM Corporation - initial API and implementation
- *******************************************************************************/
-package org.eclipse.jdt.internal.compiler.ast;
-
-import org.eclipse.jdt.internal.compiler.ASTVisitor;
-import org.eclipse.jdt.internal.compiler.impl.*;
-import org.eclipse.jdt.internal.compiler.classfmt.ClassFileConstants;
-import org.eclipse.jdt.internal.compiler.codegen.*;
-import org.eclipse.jdt.internal.compiler.flow.*;
-import org.eclipse.jdt.internal.compiler.lookup.*;
-
-public class WhileStatement extends Statement {
-
- public Expression condition;
- public Statement action;
- private Label breakLabel, continueLabel;
- int preCondInitStateIndex = -1;
- int condIfTrueInitStateIndex = -1;
- int mergedInitStateIndex = -1;
-
- public WhileStatement(Expression condition, Statement action, int s, int e) {
-
- this.condition = condition;
- this.action = action;
- // remember useful empty statement
- if (action instanceof EmptyStatement) action.bits |= IsUsefulEmptyStatementMASK;
- sourceStart = s;
- sourceEnd = e;
- }
-
- public FlowInfo analyseCode(
- BlockScope currentScope,
- FlowContext flowContext,
- FlowInfo flowInfo) {
-
- breakLabel = new Label();
- continueLabel = new Label();
-
- Constant cst = this.condition.constant;
- boolean isConditionTrue = cst != NotAConstant && cst.booleanValue() == true;
- boolean isConditionFalse = cst != NotAConstant && cst.booleanValue() == false;
-
- cst = this.condition.optimizedBooleanConstant();
- boolean isConditionOptimizedTrue = cst != NotAConstant && cst.booleanValue() == true;
- boolean isConditionOptimizedFalse = cst != NotAConstant && cst.booleanValue() == false;
-
- preCondInitStateIndex =
- currentScope.methodScope().recordInitializationStates(flowInfo);
- LoopingFlowContext condLoopContext;
- FlowInfo postCondInfo =
- this.condition.analyseCode(
- currentScope,
- (condLoopContext =
- new LoopingFlowContext(flowContext, this, null, null, currentScope)),
- flowInfo);
-
- LoopingFlowContext loopingContext;
- FlowInfo actionInfo;
- if (action == null
- || (action.isEmptyBlock() && currentScope.environment().options.complianceLevel <= ClassFileConstants.JDK1_3)) {
- condLoopContext.complainOnFinalAssignmentsInLoop(currentScope, postCondInfo);
- if (isConditionTrue) {
- return FlowInfo.DEAD_END;
- } else {
- FlowInfo mergedInfo = postCondInfo.initsWhenFalse().unconditionalInits();
- if (isConditionOptimizedTrue){
- mergedInfo.setReachMode(FlowInfo.UNREACHABLE);
- }
- mergedInitStateIndex =
- currentScope.methodScope().recordInitializationStates(mergedInfo);
- return mergedInfo;
- }
- } else {
- // in case the condition was inlined to false, record the fact that there is no way to reach any
- // statement inside the looping action
- loopingContext =
- new LoopingFlowContext(
- flowContext,
- this,
- breakLabel,
- continueLabel,
- currentScope);
- if (isConditionFalse) {
- actionInfo = FlowInfo.DEAD_END;
- } else {
- actionInfo = postCondInfo.initsWhenTrue().copy();
- if (isConditionOptimizedFalse){
- actionInfo.setReachMode(FlowInfo.UNREACHABLE);
- }
- }
-
- // for computing local var attributes
- condIfTrueInitStateIndex =
- currentScope.methodScope().recordInitializationStates(
- postCondInfo.initsWhenTrue());
-
- if (!this.action.complainIfUnreachable(actionInfo, currentScope, false)) {
- actionInfo = this.action.analyseCode(currentScope, loopingContext, actionInfo);
- }
-
- // code generation can be optimized when no need to continue in the loop
- if (!actionInfo.isReachable() && !loopingContext.initsOnContinue.isReachable()) {
- continueLabel = null;
- } else {
- // TODO (philippe) should simplify in one Loop context
- condLoopContext.complainOnFinalAssignmentsInLoop(currentScope, postCondInfo);
- actionInfo = actionInfo.mergedWith(loopingContext.initsOnContinue.unconditionalInits());
- loopingContext.complainOnFinalAssignmentsInLoop(currentScope, actionInfo);
- }
- }
-
- // end of loop
- FlowInfo mergedInfo = FlowInfo.mergedOptimizedBranches(
- loopingContext.initsOnBreak,
- isConditionOptimizedTrue,
- postCondInfo.initsWhenFalse(),
- isConditionOptimizedFalse,
- !isConditionTrue /*while(true); unreachable(); */);
- mergedInitStateIndex = currentScope.methodScope().recordInitializationStates(mergedInfo);
- return mergedInfo;
- }
-
- /**
- * While code generation
- *
- * @param currentScope org.eclipse.jdt.internal.compiler.lookup.BlockScope
- * @param codeStream org.eclipse.jdt.internal.compiler.codegen.CodeStream
- */
- public void generateCode(BlockScope currentScope, CodeStream codeStream) {
-
- if ((bits & IsReachableMASK) == 0) {
- return;
- }
- int pc = codeStream.position;
- breakLabel.initialize(codeStream);
-
- // generate condition
- if (continueLabel == null) {
- // no need to reverse condition
- if (condition.constant == NotAConstant) {
- condition.generateOptimizedBoolean(
- currentScope,
- codeStream,
- null,
- breakLabel,
- true);
- }
- } else {
- continueLabel.initialize(codeStream);
- if (!(((condition.constant != NotAConstant)
- && (condition.constant.booleanValue() == true))
- || (action == null)
- || action.isEmptyBlock())) {
- int jumpPC = codeStream.position;
- codeStream.goto_(continueLabel);
- codeStream.recordPositionsFrom(jumpPC, condition.sourceStart);
- }
- }
- // generate the action
- Label actionLabel;
- (actionLabel = new Label(codeStream)).place();
- if (action != null) {
- // Required to fix 1PR0XVS: LFRE:WINNT - Compiler: variable table for method appears incorrect
- if (condIfTrueInitStateIndex != -1) {
- // insert all locals initialized inside the condition into the action generated prior to the condition
- codeStream.addDefinitelyAssignedVariables(
- currentScope,
- condIfTrueInitStateIndex);
- }
- action.generateCode(currentScope, codeStream);
- // May loose some local variable initializations : affecting the local variable attributes
- if (preCondInitStateIndex != -1) {
- codeStream.removeNotDefinitelyAssignedVariables(
- currentScope,
- preCondInitStateIndex);
- }
-
- }
- // output condition and branch back to the beginning of the repeated action
- if (continueLabel != null) {
- continueLabel.place();
- condition.generateOptimizedBoolean(
- currentScope,
- codeStream,
- actionLabel,
- null,
- true);
- }
- breakLabel.place();
-
- // May loose some local variable initializations : affecting the local variable attributes
- if (mergedInitStateIndex != -1) {
- codeStream.removeNotDefinitelyAssignedVariables(currentScope, mergedInitStateIndex);
- codeStream.addDefinitelyAssignedVariables(currentScope, mergedInitStateIndex);
- }
- codeStream.recordPositionsFrom(pc, this.sourceStart);
- }
-
- public void resolve(BlockScope scope) {
-
- TypeBinding type = condition.resolveTypeExpecting(scope, BooleanBinding);
- condition.implicitWidening(type, type);
- if (action != null)
- action.resolve(scope);
- }
-
- public StringBuffer printStatement(int tab, StringBuffer output) {
-
- printIndent(tab, output).append("while ("); //$NON-NLS-1$
- condition.printExpression(0, output).append(')');
- if (action == null)
- output.append(';');
- else
- action.printStatement(tab + 1, output);
- return output;
- }
-
- public void traverse(
- ASTVisitor visitor,
- BlockScope blockScope) {
-
- if (visitor.visit(this, blockScope)) {
- condition.traverse(visitor, blockScope);
- if (action != null)
- action.traverse(visitor, blockScope);
- }
- visitor.endVisit(this, blockScope);
- }
-}
projects / org.ibex.tool.git / blobdiff